Literature References: Prepd by sulfonation of toluene with 96-100% H2SO4; when carried out at 75° the compn of the reaction product is 75% para-, 19% ortho- and 6% meta-toluenesulfonic acid. Convenient lab prepn: L. F. Fieser, Experiments in Organic Chemistry (Boston, 3rd ed., 1955) p 144. The separation of toluene from petroleum fractions can be accomplished by sulfonation with H2SO4 at 60°.